/*
 * Copyright (c) 2007-2012, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Copyright 2002-2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: ObjectVector.java,v 1.2.4.1 2005/09/15 08:15:51 suresh_emailid Exp $
 */
package com.sun.org.apache.xml.internal.utils;

/**
 * A very simple table that stores a list of objects.
 *
 * This version is based on a "realloc" strategy -- a simle array is
 * used, and when more storage is needed, a larger array is obtained
 * and all existing data is recopied into it. As a result, read/write
 * access to existing nodes is O(1) fast but appending may be O(N**2)
 * slow.
 * @xsl.usage internal
 */
public class ObjectVector implements Cloneable {

    /** Size of blocks to allocate          */
    protected int m_blocksize;

    /** Array of objects          */
    protected Object m_map[];

    /** Number of ints in array          */
    protected int m_firstFree = 0;

    /** Size of array          */
    protected int m_mapSize;

    /**
     * Default constructor.  Note that the default
     * block size is very small, for small lists.
     */
    public ObjectVector() {

        m_blocksize = 32;
        m_mapSize = m_blocksize;
        m_map = new Object[m_blocksize];
    }

    /**
     * Construct a IntVector, using the given block size.
     *
     * @param blocksize Size of block to allocate
     */
    public ObjectVector(int blocksize) {

        m_blocksize = blocksize;
        m_mapSize = blocksize;
        m_map = new Object[blocksize];
    }

    /**
     * Construct a IntVector, using the given block size.
     *
     * @param blocksize Size of block to allocate
     */
    public ObjectVector(int blocksize, int increaseSize) {

        m_blocksize = increaseSize;
        m_mapSize = blocksize;
        m_map = new Object[blocksize];
    }

    /**
     * Copy constructor for ObjectVector
     *
     * @param v Existing ObjectVector to copy
     */
    public ObjectVector(ObjectVector v) {
        m_map = new Object[v.m_mapSize];
        m_mapSize = v.m_mapSize;
        m_firstFree = v.m_firstFree;
        m_blocksize = v.m_blocksize;
        System.arraycopy(v.m_map, 0, m_map, 0, m_firstFree);
    }

    /**
     * Get the length of the list.
     *
     * @return length of the list
     */
    public final int size() {
        return m_firstFree;
    }

    /**
     * Get the length of the list.
     *
     * @return length of the list
     */
    public final void setSize(int sz) {
        m_firstFree = sz;
    }

    /**
     * Append an object onto the vector.
     *
     * @param value Object to add to the list
     */
    public final void addElement(Object value) {

        if ((m_firstFree + 1) >= m_mapSize) {
            m_mapSize += m_blocksize;

            Object newMap[] = new Object[m_mapSize];

            System.arraycopy(m_map, 0, newMap, 0, m_firstFree + 1);

            m_map = newMap;
        }

        m_map[m_firstFree] = value;

        m_firstFree++;
    }

    /**
     * Append several Object values onto the vector.
     *
     * @param value Object to add to the list
     */
    public final void addElements(Object value, int numberOfElements) {

        if ((m_firstFree + numberOfElements) >= m_mapSize) {
            m_mapSize += (m_blocksize + numberOfElements);

            Object newMap[] = new Object[m_mapSize];

            System.arraycopy(m_map, 0, newMap, 0, m_firstFree + 1);

            m_map = newMap;
        }

        for (int i = 0; i < numberOfElements; i++) {
            m_map[m_firstFree] = value;
            m_firstFree++;
        }
    }

    /**
     * Append several slots onto the vector, but do not set the values.
     *
     * @param numberOfElements number of slots to append
     */
    public final void addElements(int numberOfElements) {

        if ((m_firstFree + numberOfElements) >= m_mapSize) {
            m_mapSize += (m_blocksize + numberOfElements);

            Object newMap[] = new Object[m_mapSize];

            System.arraycopy(m_map, 0, newMap, 0, m_firstFree + 1);

            m_map = newMap;
        }

        m_firstFree += numberOfElements;
    }

    /**
     * Inserts the specified object in this vector at the specified index.
     * Each component in this vector with an index greater or equal to
     * the specified index is shifted upward to have an index one greater
     * than the value it had previously.
     *
     * @param value Object to insert
     * @param at Index of where to insert
     */
    public final void insertElementAt(Object value, int at) {

        if ((m_firstFree + 1) >= m_mapSize) {
            m_mapSize += m_blocksize;

            Object newMap[] = new Object[m_mapSize];

            System.arraycopy(m_map, 0, newMap, 0, m_firstFree + 1);

            m_map = newMap;
        }

        if (at <= (m_firstFree - 1)) {
            System.arraycopy(m_map, at, m_map, at + 1, m_firstFree - at);
        }

        m_map[at] = value;

        m_firstFree++;
    }

    /**
     * Remove all elements objects from the list.
     */
    public final void removeAllElements() {

        for (int i = 0; i < m_firstFree; i++) {
            m_map[i] = null;
        }

        m_firstFree = 0;
    }

    /**
     * Removes the first occurrence of the argument from this vector.
     * If the object is found in this vector, each component in the vector
     * with an index greater or equal to the object's index is shifted
     * downward to have an index one smaller than the value it had
     * previously.
     *
     * @param s Object to remove from array
     *
     * @return True if the object was removed, false if it was not found
     */
    public final boolean removeElement(Object s) {

        for (int i = 0; i < m_firstFree; i++) {
            if (m_map[i] == s) {
                if ((i + 1) < m_firstFree)
                    System.arraycopy(m_map, i + 1, m_map, i - 1, m_firstFree - i);
                else
                    m_map[i] = null;

                m_firstFree--;

                return true;
            }
        }

        return false;
    }

    /**
     * Deletes the component at the specified index. Each component in
     * this vector with an index greater or equal to the specified
     * index is shifted downward to have an index one smaller than
     * the value it had previously.
     *
     * @param i index of where to remove an object
     */
    public final void removeElementAt(int i) {

        if (i > m_firstFree)
            System.arraycopy(m_map, i + 1, m_map, i, m_firstFree);
        else
            m_map[i] = null;

        m_firstFree--;
    }

    /**
     * Sets the component at the specified index of this vector to be the
     * specified object. The previous component at that position is discarded.
     *
     * The index must be a value greater than or equal to 0 and less
     * than the current size of the vector.
     *
     * @param value object to set
     * @param index Index of where to set the object
     */
    public final void setElementAt(Object value, int index) {
        m_map[index] = value;
    }

    /**
     * Get the nth element.
     *
     * @param i index of object to get
     *
     * @return object at given index
     */
    public final Object elementAt(int i) {
        return m_map[i];
    }

    /**
     * Tell if the table contains the given Object.
     *
     * @param s object to look for
     *
     * @return true if the object is in the list
     */
    public final boolean contains(Object s) {

        for (int i = 0; i < m_firstFree; i++) {
            if (m_map[i] == s)
                return true;
        }

        return false;
    }

    /**
     * Searches for the first occurence of the given argument,
     * beginning the search at index, and testing for equality
     * using the equals method.
     *
     * @param elem object to look for
     * @param index Index of where to begin search
     * @return the index of the first occurrence of the object
     * argument in this vector at position index or later in the
     * vector; returns -1 if the object is not found.
     */
    public final int indexOf(Object elem, int index) {

        for (int i = index; i < m_firstFree; i++) {
            if (m_map[i] == elem)
                return i;
        }

        return java.lang.Integer.MIN_VALUE;
    }

    /**
     * Searches for the first occurence of the given argument,
     * beginning the search at index, and testing for equality
     * using the equals method.
     *
     * @param elem object to look for
     * @return the index of the first occurrence of the object
     * argument in this vector at position index or later in the
     * vector; returns -1 if the object is not found.
     */
    public final int indexOf(Object elem) {

        for (int i = 0; i < m_firstFree; i++) {
            if (m_map[i] == elem)
                return i;
        }

        return java.lang.Integer.MIN_VALUE;
    }

    /**
     * Searches for the first occurence of the given argument,
     * beginning the search at index, and testing for equality
     * using the equals method.
     *
     * @param elem Object to look for
     * @return the index of the first occurrence of the object
     * argument in this vector at position index or later in the
     * vector; returns -1 if the object is not found.
     */
    public final int lastIndexOf(Object elem) {

        for (int i = (m_firstFree - 1); i >= 0; i--) {
            if (m_map[i] == elem)
                return i;
        }

        return java.lang.Integer.MIN_VALUE;
    }

    /*
     * Reset the array to the supplied size.
     *
     * @param size
     */
    public final void setToSize(int size) {

        Object newMap[] = new Object[size];

        System.arraycopy(m_map, 0, newMap, 0, m_firstFree);
        m_mapSize = size;

        m_map = newMap;

    }

    /**
     * Returns clone of current ObjectVector
     *
     * @return clone of current ObjectVector
     */
    public Object clone() throws CloneNotSupportedException {
        return new ObjectVector(this);
    }
}
